Question

I come from a microcontroller programming world, and I am learning to program on iOS,

I have a question that is being bothering me:

• how to know the physical address of a the memory allocated to an object?

   NSString *nombre = [[NSString alloc] initWithString:@"nombreName"];
  

like the hexa address?? where to see this?

• how big is the heap? can I see the heap at the beggining and after allocating to the objects?

Answer 1

Use gdb to inspect objects at runtime while debugging.

I’ve created a simple UIView object as,

UIView *someObject = [[UIView alloc] init];

and set a breakpoint on this line,

Stepping over this line so that someObject’s memory is allocated, and then run po or print object on gdb shows the hex address of this object – 0x9304090.

(gdb) po someObject
<UIView: 0x9304090; frame = (0 0; 0 0); layer = <CALayer: 0x4b1b730>>

If the object’s description method has been overridden, you may not see the hex address. For those objects, simply print the pointer

(gdb) p someObject
$2 = (UIView *) 0x9304090

or cast it to an int to see the memory location as a decimal.

(gdb) p (int) someObject
$3 = 154157200